This is an interdisciplinary program aimed at increasing the basic understanding of how innate behavior patterns (i.e. "fixed action patterns") and recognition mechanisms (i.e. "innate releasing mechanisms") are coded in and controlled by the nervous system. For this purpose, anuran (toads and frogs) acoustic behaviors (calling and responses to calls) are being utilized. These behaviors are especially appropriate because of their relative simplicity, the species-specificity of some calls, and the fact that some calls can be elicited in essentially normal form by brain stimulation. Anurans are especially appropriate because of their high tolerance of radical surgical procedures, accessibility and simplicity of their nervous systems, and relatively ready availability and maintenance. A major method to be used is the isolated brainstem preparation developed in this lab. In this technique, the brainstem of a frog is removed and maintained in a tissue bath. The calling circuits are then triggered by electrical brain stimulation and neural correlates of calling are recorded from the brainstem and attached nerves. This method will be used with various electrophysiological, lesioning, neuroanatomical, and neuroendocrinological techniques to study the calling circuits of adult anurans and to study the development of these circuits in juveniles. The type of information obtained will be important for a better understanding of the physiological and anatomical basis of "innate" behaviors. "Innate" behavior patterns are also important in normal and abnormal human behavior although, in this species, such behavior is often obscured by more conspicuous (and better-studied) "learned" behaviors.